Implement watch events

tasks/watch.js

@@ -78,8 +78,17 @@ module.exports = function(grunt) {
         // On changed/added/deleted
         this.on('all', function(status, filepath) {
           filepath = path.relative(process.cwd(), filepath);
-          taskrun.changedFiles[filepath] = status;
-          taskrun[options.nospawn ? 'nospawn' : 'spawn'](i, target.tasks, options, done);
+
+          // Emit watch events if anyone is listening
+          if (grunt.event.listeners('watch').length > 0) {
+            grunt.event.emit('watch', status, filepath);
+          }
+
+          // Run tasks if any have been specified
+          if (target.tasks) {
+            taskrun.changedFiles[filepath] = status;
+            taskrun[options.nospawn ? 'nospawn' : 'spawn'](i, target.tasks, options, done);
+          }
         });
 
         // On watcher error

test/fixtures/events/Gruntfile.js

@@ -0,0 +1,18 @@
+module.exports = function(grunt) {
+  'use strict';
+
+  grunt.initConfig({
+    watch: {
+      files: ['lib/*.js']
+    }
+  });
+
+  // Load this watch task
+  grunt.loadTasks('../../../tasks');
+
+  // trigger on watch events
+  grunt.event.on('watch', function(action, filepath) {
+    grunt.log.writeln(filepath + ' was indeed ' + action);
+    if (action === 'deleted') { grunt.util.exit(0); }
+  });
+};

test/fixtures/events/lib/one.js

@@ -0,0 +1 @@
+var one = true;

test/tasks/events_test.js

@@ -0,0 +1,48 @@
+'use strict';
+
+var grunt = require('grunt');
+var path = require('path');
+var fs = require('fs');
+var helper = require('./helper');
+
+var fixtures = helper.fixtures;
+
+function cleanUp() {
+  helper.cleanUp([
+    'events/node_modules',
+    'events/lib/added.js'
+  ]);
+}
+
+exports.events = {
+  setUp: function(done) {
+    cleanUp();
+    fs.symlinkSync(path.join(__dirname, '../../node_modules'), path.join(fixtures, 'events', 'node_modules'));
+    done();
+  },
+  tearDown: function(done) {
+    cleanUp();
+    done();
+  },
+  events: function(test) {
+    test.expect(3);
+    var cwd = path.resolve(fixtures, 'events');
+    var assertWatch = helper.assertTask('watch', {cwd: cwd});
+    assertWatch([function() {
+      var write = 'var one = true;';
+      grunt.file.write(path.join(cwd, 'lib', 'added.js'), write);
+      setTimeout(function() {
+        grunt.file.write(path.join(cwd, 'lib', 'one.js'), write);
+      }, 250);
+      setTimeout(function() {
+        grunt.file.delete(path.join(cwd, 'lib', 'added.js'));
+      }, 500);
+    }], function(result) {
+      helper.verboseLog(result);
+      test.ok(result.indexOf('lib/added.js was indeed added') !== -1, 'event emitted when file added');
+      test.ok(result.indexOf('lib/one.js was indeed changed') !== -1, 'event emitted when file changed');
+      test.ok(result.indexOf('lib/added.js was indeed deleted') !== -1, 'event emitted when file deleted');
+      test.done();
+    });
+  },
+};